Evidence that a developmentally regulated glycoprotein is target of adhesion-blocking Fab in reaggregating Dictyostelium
Evidence that a developmentally regulated glycoprotein is target of adhesion-blocking Fab in reaggregating Dictyostelium
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有证据表明，发育调节糖蛋白是盘基网柄菌重新聚集中粘附阻断 Fab 的靶标
作者：
C. Steinemann;R. Parish
在聚集的盘基网柄藻细胞中，粘附阻断Fab的靶位点是分子量约为82，000的质膜糖蛋白（参考文献1-3），其在聚集后不再合成，并从质膜上消失4，5。然而，由于细胞粘附在分化的后期阶段仍然很重要6 -8，因此可能有另一种蛋白质接管其功能。一种候选物是糖蛋白（分子量95，000），其合成开始于尖端阶段并持续至发育完成5，8。这两种蛋白质都具有很强的抗原性。当假原质团（“蛞蝓”，发育后期）分解并重新接种时，细胞比以前更快地重演先前的形态变化序列6 -8，尽管分子量为82，000的糖蛋白在重新聚集期间不会重新合成4，8。我们在这里报告，针对蛞蝓质膜的单价抗体（Fab）通过与分子量为95，000的糖蛋白结合来抑制再聚集，因此似乎参与细胞粘附。
The target site of adhesion-blocking Fab in aggregating Dictyostelium discoideum cells is a plasma membrane glycoprotein of approximate molecular weight 82,000 (refs 1–3), which is no longer synthesized after aggregation, and disappears from the plasma membrane4,5. However, since cell adhesion remains important during later stages of differentiation6–8, presumably another protein(s) takes over its function. One candidate is a glycoprotein (molecular weight 95,000) whose synthesis commences at the tip stage and continues until the completion of development5,8. Both proteins are strongly antigenic4. When pseudoplasmodia (‘slugs’, a late developmental stage) are disaggregated and replated, the cells recapitulate the previous sequence of morphological changes much more quickly than before6–8, although the glycoprotein of molecular weight 82,000 is not resynthesized during reaggregation4,8. We report here that monovalent antibody (Fab) directed against slug plasma membranes inhibits reaggregation by binding to the glycoprotein of molecular weight 95,000 which thus seems to be involved in cell adhesion.